1. Field of the Invention
This invention relates to a collapsible swimming pool and more specifically to a pool made up of a plurality of sections which can be easily set up and quickly interlocked with each other to form an integrated swimming pool, or collapsed and nested one on top of the other for the purpose of compact storage.
2. Discussion of the Prior Art
It has long been recognized in the prior art, especially in geographic areas having seasons that present cold and freezing weather, that it is desirable and in some circumstances necessary for swimming pools to be emptied of water and stored away until warm weather returns. The simplest type of prior art swimming pool is made in one piece, usually molded from plastic material. Such one-piece pools are relatively small but even the smallest children's size pools of this type must be up to six or eight feet in diameter and 12 to 18 inches in depth in order to effectively function as an enjoyable swimming pool. As such pools are not collapsible they present storage problems for the average pool owner. In addition, handling of such one-piece pools when storing frequently results in cracking and breaking of the plastic and often such pools become unusable after only a single season and must be replaced at some expense.
In an effort to overcome the storage problem presented by the one-piece molded pools, it has been suggested to make a one-piece pool out of flexible sheet material such as vinyl plastic and provide it with a tubular inflatable side wall or walls. While inflatable side wall pools can be collapsed, they are difficult to fold up and have the disadvantage of the tubular side walls being easily punctured. Further, inflatable side walls do not have sufficient strength in tension or in vertical compression to retain an appreciable depth of water and such pools are undesirably shallow and functionally unattractive to all but the smallest children.
In order to overcome the disadvantages, of the inflatable side wall pools, U.S. Pat. No. 1,961,061 issued May 29, 1934 to M. L. McCulloch teaches the use of a one-piece pool made of flexible material. The areas of this pool that join the side wall and base are reinforced by additional overlapping layers of material and the side walls themselves are also reinforced by additional thicknesses of material. In addition, it is suggested that ropes encircle the side walls for providing further reinforcement. The extreme upper edge is stiffened by wood inserts, A similar design for a one-piece pool is taught in U.S. Pat. No. 2,839,762 issued June 24, 1958 to R. Nomura. While pools of this general design will perform satisfactorily, the reinforcing used makes them bulky and difficult to collapse. In cooler weather, the material of which the pool is made stiffens and does not lend itself to easy folding into a compact unit for storage.
In response to the need for an improved collapsible swimming pool, U.S. Pat. No. 2,939,153 issued June 7, 1960 to C. R. Arnold et al teaches that the side wall of the pool be made of a plurality of rectangular frame sections. The pieces which make up the frame sections include a plurality of sockets which are used to secure the plurality of individual frame pieces together to form a cylindrical wall. A continuous metal reinforcing wall is installed inside the cylindrical wall and a waterproof liner is then added to complete the pool. A pool of this design includes a large number of parts and the complexity of the frame assembly does not permit quick easy assembly and disassembly. Further, the large number of frame members and the continuous reinforcing wall are not compact when collapsed and present storage problems. Further, such pools have a high number of individual pieces which increases the risk that one or more of the pieces may be lost.
Another type of collapsible swimming pool is taught in U.S. Pat. No. 2,861,277 issued Nov. 25, 1958 to L. Hermann. This patent teaches the use of a plurality of interlocking aluminum extrusions to form the side wall of the pool. The side wall extrusions do not include any bottom wall portions and are each provided with a slotted channel defining a cylindrical chamber on one vertical edge and a cylindrical bead on the other edge. The extrusions must be slid vertically downward over a smaller vertically extending cylindrical bead on an adjacent wall section. Channel-shaped members are added to enclose the upper edges of the extrusion. Such a pool also utilizes a large number of separate component parts which require time consuming assembly and disassembly, and compact storage is not easily achieved. Further, any distortion or bending of the extruded channel or bead from a straight line will make it very difficult, if not impossible, to assemble or disassemble the pool because of binding of the beads within their respective channels.